Effect of Addition of Multi-Component Lanthanides to LiCl-KCl Eutectic on Thermal and Electrochemical Properties

Abstract

Pyrochemical or pyrometallurgical processing using LiCl-KCl molten salt systems is considered one of the alternatives to the PUREX process for safe and proliferation resistant recovery of nuclear fuel elements from the spent fuels. Most of the available thermodynamic data on the molten salt systems pertain to binary or ternary systems. When multiple fission product elements are present in the electrolyte, the reduction behavior of the actinides could be significantly altered because of possible under potential reduction of lanthanides and slower diffusion kinetics of actinides. This presentation reports the variations in melting point and electrochemical behavior of LiCl + KCl eutectic mixture containing multi-components of RECl3 additions. No significant change in the melting temperature was observed with the addition of multiple lanthanide chlorides o the LiCl-KCl eutectic. However, the reduction potential was shifted in the positive direction with the addition of multiple lanthanides, especially when CeCl3 was one of the constituent.